The discovery of leptin in 1994 caused a lot of excitement as scientists hoped they could use it to help people control their weight. Leptin is a hormone secreted by fat cells that affects the way the body stores and burns energy. It is sometimes known as a satiety drug because it reduces appetite.
Researchers soon learned some facts about leptin that debunked their original assumptions. They found that people with obesity had plenty of leptin in their bodies but still gained weight. They presumed that people who are overweight may have a condition called leptin resistance. Researchers also learned that leptin supplements don't work since they can't get past the blood-brain barrier and are metabolized by the body.
In addition to regulating appetite, leptin has been found to play many roles in the body, including boosting the immune system, reducing inflammation, and creating healthy bones. However, these roles require additional research to be fully supported.
Leptin works in combination with another hormone, ghrelin, which signals hunger. Together these are called the hunger hormones since they control how often and how much you want to eat. Yet, scientists think that leptin plays a more important role than ghrelin.
Congenital leptin deficiency results in uncontrolled hunger. It is usually discovered early in life when children exhibit severe obesity and delayed puberty. Injections of a leptin analog are effective in controlling this condition.
Generalized lipodystrophy is a serious condition in which individuals have almost no body fat. Often they accumulate fat in their organs, and may develop metabolic health risks such as diabetes. Because they have few fat cells, people with this condition don't produce enough leptin. Therefore, they are treated with injections of a synthetic leptin.
In order for leptin to work properly in the body, you need plenty of high-quality sleep. One study found that people who were sleep-deprived had high levels of ghrelin, which makes you hungry, and lower levels of leptin, which makes you feel satisfied.
Your choice of food is also important. Today researchers are looking at the relationship between leptin and triglycerides, a type of fat also known as lipids. Research shows that high triglycerides seem to impact the way leptin works in the body. A diet that is designed to lower triglycerides could help to boost leptin in your body.
And the reverse may be true as well. Being very hungry at bedtime can cause lower leptin levels and that could interfere with your sleep. In fact, a lack of sleep can be a sign of starvation in people with a serious lack of body fat or daily calories.
Other health problems can mess with your leptin signaling too. For example, chronic inflammation and high levels of triglycerides (a kind of fat found in your blood) can make it harder for leptin to cross the blood-brain barrier.
But you can target insulin resistance, which often occurs alongside leptin resistance. Improve your sensitivity to insulin with medication, a healthy diet, plenty of exercise, and good sleep habits, and your leptin resistance may improve as well.
Though scientists have just scratched the surface when it comes to leptin, they know it plays a part in various aspects of bodily health. That includes bone health, good immune function, and fertility.
The amount of leptin in your blood is directly proportional to the amount of adipose tissue your body has. In other words, the less body fat, the less leptin you have, and the more body fat, the more leptin you have.
Normal value ranges for leptin levels may vary slightly among different laboratories. Be sure to look at the range of normal values listed on your laboratory report or ask your healthcare provider if you have questions about your results.
Since the amount of leptin in your blood is directly proportional to the amount of adipose tissue (body fat), having obesity results in high levels of leptin (hyperleptinemia). This can cause a lack of sensitivity to leptin, a condition known as leptin resistance.
The seeming lack of leptin in leptin resistance also causes your body to enter starvation mode. In an effort to save energy, your brain decreases your energy levels and makes you use fewer calories at rest.
Leptin supplements contain various nutrients that are said to improve leptin sensitivity and promote fullness, but research is lacking. African mango may help lower levels of the hormone and improve sensitivity, but more studies are needed.
Increasing physical activity, getting enough sleep, decreasing sugar intake and including more fish in your diet are some steps you can take to improve leptin sensitivity. Lowering your blood triglycerides is important, too.
Layout table for study information Study Type : Interventional (Clinical Trial) EstimatedEnrollment : 40 participants Allocation: Randomized Intervention Model: Parallel Assignment Masking: Double (Participant, Investigator) Primary Purpose: Treatment Official Title: Leptin Treatment for Prevention of the Metabolic and Endocrine Sequelae of a Decreased Caloric Intake: Studies of Patients on a Very Low Calorie Diet Study Start Date : March 2001 Actual Primary Completion Date : November 2006 Actual Study Completion Date : June 2009 Resource links provided by the National Library of Medicine MedlinePlus related topics: Weight Control U.S. FDA Resources Arms and Interventions Go to Top of Page Study Description Study Design Arms and Interventions Outcome Measures Eligibility Criteria Contacts and Locations More Information Arm Intervention/treatment Experimental: VLCD and leptinVery low calorie diet formula providing 800 calories per day and leptin treatment. Drug: LeptinLeptin is an adipocyte hormone that functions as an afferent signal in a feedback loop regulating body weightOther Names:A-100Recombinant-methionyl Human Leptin (r-metHuLeptin) Active Comparator: placeboVery low calorie diet and placebo treatment Behavioral: Very Low Calorie Dietplacebo injections Outcome Measures Go to Top of Page Study Description Study Design Arms and Interventions Outcome Measures Eligibility Criteria Contacts and Locations More Information Primary Outcome Measures : energy expenditure after 10% and 20% weight loss, achieved by a VLCD with or without A-100 treatment [ Time Frame: Testing period 2,3 and 4 after 10% and 20% weight loss ] Secondary Outcome Measures : endocrine and behavioral parameters [ Time Frame: testing period 2, 3 and 4. After 10% and 20% weight loss ] Eligibility CriteriaGo to Top of Page Study Description Study Design Arms and Interventions Outcome Measures Eligibility Criteria Contacts and Locations More Information Information from the National Library of Medicine Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies. Layout table for eligibility information Ages Eligible for Study: 20 Years to 45 Years (Adult) Sexes Eligible for Study: Female Accepts Healthy Volunteers: Yes Criteria Inclusion Criteria:
Three-dimensional reconstruction of the brain, indicating the accumulation of fluorescent leptin (leptin-CW800) in the median eminence (ME) and choroid plexus (CP) of lean (Chow, standard diet) (i) and diet-induced obesity (DIO) (ii) mice. From , visit
Irrespective of the mechanism(s) responsible for leptin resistance, it is plausible to use leptin for weight loss if the leptin receptor and the underlying intracellular signaling pathway are specifically activated in the corresponding parts of the brain. Different methodological approaches have been used (Figure 2).
One of the most intuitive approaches is to increase the passage of leptin through the BBB. It is important to point out that many strategies used to increase the passage of substances through the BBB in different pathological conditions consider that the BBB maintains its physiological properties; however, the pathological condition itself can modify the integrity of the BBB, promoting the failure of these therapies. Therefore, it is necessary that therapies based on an increase in the passage of leptin through the BBB ensure the integrity of the BBB. Strategies that improve the passage of leptin to the brain include the development of modifications in the structure of leptin or leptin analogues as well as the development of new leptin receptor agonists with increased BBB permeability. One of the most widely used modifications in the development of targeted therapeutic agents in the brain is the addition of hydrophilic polyethylene glycol (PEG)-containing polymers. However, PEG-modified leptin is unable to pass through the BBB and thereby reduce body weight in humans [35,36,37]. Other strategies based on the addition of a glucidic residue, such as leptin fused with a trans-activating transcriptional activator Tat (Tat-Leptin) or pluronic, have shown an increase in BBB transportation in DIO mice [38,39,40,41]. In addition, new techniques such as PASylation of leptin, which aim to prolong its half-life, can increase the effectiveness of leptin .
Several studies have shown that conventional leptin replacement therapies in obese subjects have very modest effects. To this point, several studies have proposed combinatorial therapies of the different hormones involved in energy regulation to act upon various mechanisms of action and avoid compensatory mechanisms. In leptin-resistant rats, the combination of amylin, a 37-amino acid-long anorexigenic hormone, with leptin results in the greater inhibition of food intake and loss in body weight, when compared to leptin monotherapy, as well as improved metabolism in the long term [47,48,49,50,51,52,53,54]. In humans, a combination of pramlintide acetate (a synthetic analog of amylin) and metreleptin (a methionyl form of leptin) has been used, which caused more weight loss compared to that observed individually with these compounds [55,56]. However, this therapeutic strategy was suspended because of the development of anti-metreleptin antibodies. 781b155fdc